Functionalization of thermoplastic resin to gain certain functional properties by chemical or irradiation method is well known in the art. For instance, corona treatment including plasma to treat surface of thermoplastic polymer is commonly used.
In US20060177489A1, a method for attaching a chitosan to the surface of the polymers that includes at least one rehydration step to provide more effective and stable chitosan coating was provided. The articles made with those polymers provide antibacterial and anti-odor properties. Plasma treatment as one of the treatments for pre-treating the surface of the polymers to acquire a wettable surface before chitosan coating was described in that patent.
US20070104901A1 also described that an important use of irradiative treatments including plasma on polymer sheets and films is to induce cross-linking between molecules of the irradiated material. It also cited some older US patents such as U.S. Pat. No. 4,737,391 and U.S. Pat. No. 5,055,328, which disclosed different irradiation methods to treat polymer surface.
However, there is no literature teaching or suggesting using plasma treatment to modify thermoplastic resin in order to gain certain functions from forming bonds with active agents covalently. The present invention aims to fulfill this unmet need.